Conventional power plants generally recirculate condenser cooling water by utilizing cooling towers in which relatively warm water from a condenser is pumped to the top of a cooling tower and sprayed into the tower where the water makes direct contact with upwardly rising cooler air. During its downward traverse of the cooling tower, the water is cooled; and at the bottom, the cooled water is recycled to the condenser. This approach to cooling condenser water is utilized in power plants of all sizes from large-scale nuclear power plants generating power in the thousands of megawatts to small-scale, conventional power plants of more modest power range.
The energy expended in pumping condenser water to a cooling tower has been considered, heretofore, as not recoverable; but the percentage this loss bears to the total power generated is usually so small that the economics of the power plant do not justify taking steps to recover some of the pumping losses. Such losses for condenser water cooling can amount to a more significant percentage of the output of a power plant of the type which utilizes small thermal heads, such as plants which operate on geothermal, solar, or waste heat. Therefore, considerable interest exists in increasing the efficiency of such types of power plants; and the recovery of some of the condenser water pumping losses is an area of interest.
It is an object of the present invention to provide a new and improved energy-saving, direct-contact, parallel-flow heat exchanger which will increase the efficiency of a power plant by recovering some of the pumping power associated with cooling condenser water.